Z Axis not working anymore

[cordvision]

###See second post for some more infos###

Could need some help/suggestions in trouble shooting:

Finished an engraving, and when I wanted to re-run the job, he Z-Axis started making a terrible noise and is slowly dropping. In the video linked bellow, you can see and hear what I'm talking about. The Z-Axis starts dropping slowly as soon as I hit "reset" on path pilot after powering on the mill.
Other things I noticed: One of the lights on the controller is red whereas the other two controller lights are green (see picture).
Path Pilot gives a Z-Axis limit switch warning (see picture). I disabled the "home switches" and it doesn't fix the issue.

I'm thinking it must be the controller or motor. Not sure why I get the Z-Axis limit switch warning (haven't really looked into it yet) Any ideas what the issue might be?

Also, can I just switch out controllers to find out if it is a motor problem or controller problem? I could use the controller for the x axis on the z axis...




Video:






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[cordvision]

Just found out another clue to the problem: I wanted to use the x axis stepper driver to drive the z axis. When unplugging the z axis I noticed that the plug is burnt up. Looks like something shorted. Questions is: Is the short caused by the motor? If so, it would be a bad idea to plug it into the x axis driver. Could it be that just the driver is damaged? One of the lights is still on so it is at least partially working. Also, why wasn't there a fuse that blew... could have started a fire.

[Mooser]

The plugs are notably faulty as several people have had issues with them, myself included.

https://www.cnczone.com/forums/torma...connector.html

I've also blown two of the drives so far.
That said, with the help of some members here, I've replaced the faulty IRF540 MOSFET on both of those drives and they are both working now. And along with the one on the way from China, I'll have 2 spare drives on the shelf and a dozen spare mosfets.
https://www.cnczone.com/forums/torma...ve-toilet.html

I replaced that Connector with a screw terminal one while the machine was down as well

M

[cordvision]

Thanks so much for the hint! I'll be trying to solder some high current rc bullet connectors to the driver. Fingers crossed the motor and driver are still fine.

[Mooser]

If you've got a red light on the drive it's probably popped as it's an internal error. The motor connector may have caused it to pop. You can usually swap the x and y cables to test but I don't know if they will reach the z
M

[cordvision]

Wouldn't I risk burning up the x axis motor in case there is a fault with the z axis driver?

[Mooser]

The motor is not usually fried by the drive but the drive can be fried by the motor. You should be able to connect your z drive to the X or Y motor and just by powering it up you'll see if the light goes green on the drive, I'll guess it won't but that's just my experience
M

My leadshine drive from China actually got delivered this morning, speak of the devil
M

[cordvision]

Just tested it and the driver still has the red light on. This unfortunately still leaves two option: Driver only went bad and the motor is fine, or the motor is broken and shorted the driver. The second option is what worries me. If I plug the z-axis motor into a new driver, it might fry the new driver again. Is there any safe way to test if the motor is faulty? One last question: I found tons of Leadshine drivers for cheap from China. They should be exactly the same as the ones Tormach sells, right? Optically they look 100 percent identical (just missing the Tormach sticker).

[jwatte]

If there's a fail-closed MOSFET that feeds current straight to the motor, then it IS possible to burn out a motor with a bad driver, but you'd have to have it connected and heat up for a while -- presumably you'd notice it. (Don't leave it like this for minutes, because that may actually destroy the motor.)

Typically, though, motors are robust (especially steppers and brushless) and drivers are the things that have to deal with all kind of noise and load, and may burn out/zap.

[Mooser]

Never any guarantees but I'd say your motor is ok
The leadshine I just bought is identical to the tormach except for the pug where the signal goes in, the tormach on mine is a ribbon cable with 2x 5 pins and the leadshine from china is screw terminals so there's some difference there and if you check here https://www.cnczone.com/forums/torma...ml#post2107952 john posted a pic with the needed info to convert.

If you have a soldering iron and some time, changing the MOSFET was simple and the repacements are cheap and easy to get via digikey or mouser, usually get them in a couple-three days and they are only a few buck a piece, the china drive was over $100 for me (Canada) and took 3 weeks to arrive
M

[cordvision]

I'll be ordering some Mosfets. Is the IRF540NPbF or the IRF540N the right one? Or none of those?

[Mooser]

I exact ones I bought were IRF540NPBF-ND which I believe is really just lead free versions of the IRF540N. Each of the two drives I toasted had one MOSFET blown, a different one on each but only one. I bought a handful as they were cheap compared to the shipping

M

[jwatte]

Do you know that the original was IRF540N? That's a 100V 33A part, so it seems reasonable, but if you blew it, chances are you might want something beefier as replacement.
It the parts are indeed through-hole TO-220 (like the IRF540N) then there aren't that many choices these days, as most of them are surface mount now, but here's one:
https://www.digikey.com/product-deta...GE3-ND/7326318
It has slightly higher gate charge (86 nC instead of 71 nC) but that shouldn't be a big deal. It has a lot lower on resistance (and thus current tolerance,) and higher voltage tolerance (and thus robustness to transients) so it might be worth a shot if that's what you're looking for.
(The reason they don't use these everywhere is that they are $3 each instead of $1 each, which in volume, matters, but for spare parts, not so much :-)

[Mooser]

The IRF540ZPBF-ND is also available with a 36A current drain instead of the 30 or 33
I bought 6 but didn't try them as I figured it would be best to replace all of them at once
M

[cordvision]

Thank you all for your help! I'm getting some Mosfets delivered in the new few hours. Fingers crossed it works

[jwatte]

I noticed that the plug is burnt up. Looks like something shorted.

Burned contacts can mean a number of things. If the contact makes poor contact for some reason, it will generate a lot of heat, even with "normal" motor load. It can make poor contact for a bunch of reasons, including corrosion, being poorly seated, being poorly crimped, coming loose because of vibration, and even being under-specified contacts. Contacts have an amp rating, and that rating matters! Value engineers may choose to treat this as an "average" rating, and then if you end up doing full duty cycle, you burn them up.

[Zetopan]

When unplugging the z axis I noticed that the plug is burnt up.

Examine both the male and the female ends of the connection. If one of them has a round cross section while the other has a square cross section, *that* is your problem. Such mismatched connectors results in line contact rather than area contact for the current flow and this usually only happens when an idiot decides to reduce their parts costs at the expense of reliability.